The three new physics experiments by using PC sound card

Abstract

The three new experiments by using the sound card are reported in this article. Firstly, the sound velocity has been discussed from the Doppler effect, which is modulated in a circular motion by sound beats, in next it has been proposed a new method called the maximum drop method for measuring of a surface tension of liquids, and finally the modulus of elasticity of various materials was measured from the oscillation frequency unilaterally clamped plate with rectangular cross section.

The advantage of our approach is the ability to conduct experiments not only as a demonstration, but also as students’ laboratory works. Another advantage is the affordability of the used equipment, which may offer an interesting alternative to the most expensive professional kits for a variety of primary and secondary schools.

A disadvantage can be seen, especially for pupil measurements, as the requirement for high precision in the determination and measurement of partial quantities, such as for example the droplet size in the surface tension measurement or the thickness of the plate when the modulus of elasticity is measured. However, despite of the above disadvantages, a very low price, ease-of-use and comprehensibility of the experiments make it possible for students to turn their computers into measurement devices, focus their attention to improve their physical skills and, last but not least, to make physics more attractive to them.